<!--
 * @Author: Freude Xu
 * @Date: 2021-10-06 16:23:36
 * @LastEditors: Freude Xu
 * @LastEditTime: 2021-10-06 16:44:28
 * @Description: 
-->
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 200px;
            height: 200px;
            background-color: pink;
        }
    </style>
</head>

<body>
    <div>123</div>
</body>
<script>
    window.addEventListener('load', function() {
        var div = document.querySelector('div')
        window.addEventListener('resize', function() {
            //使用innerWidth获得浏览器窗口宽度
            console.log(window.innerWidth);
            console.log('变化了');
            if (window.innerWidth <= 800) {
                div.style.display = 'none';
            } else {
                div.style.display = 'block';
            }
        })
    })
</script>

</html>